This invention relates to lock pins for sliding doors and in particular to a retainer latch for preventing outside removal of lock pins from sliding doors.
A large portion of sliding doors are locked from within with a lock pin that extends into a second sliding door from a first door frame. Burglars can remove the lock pin by merely tapping or pounding the outside of the door often with cushioned impact to muffle noise and to increase a spring action of the impact. This causes the lock pin to travel horizontally out of a locking orifice in the door and thereby unlocks the sliding door. There is a wide selection of locks for lock pins available, but they are not used often by builders because they are too expensive and increase construction costs. Buyers of homes and other buildings usually are unaware of how easily an unlocked lock pin can be removed by burglars. The lock pin has the appearance of a dead-bolt lock and often provides a dangerous sense of security. Consequently, sliding doors without locks or latches for lock pins continue to be constructed and sold on a large part of dwellings and other buildings.
There is no known lock-pin latch that can be attached without modification of door frames of sliding doors either after or at the time of building construction to retain standard lock pins in place against outside tapping impact by burglars. Nor is there a known lockable lock pin that is sufficiently inexpensive that it is likely to be attached by builders or purchased by frugality-minded users and owners of buildings with un-lockable lock pins. Further yet, there is no known latch for such latch pins that can be attached so quickly and easily by users and owners of buildings that it is likely to be used. Even a renter of buildings with un-lockable lock pins on sliding doors is likely to use this invention.
Examples of different lockable pins for sliding doors can be found in U.S. Pat. Nos. 4,102,545, 4,345,448, 3,869,887, 3,709,539, and 3,490,802, but none are useable with existing non-lockable pins. None can be attached without modification of the sliding door or door frame. All are too different to describe for comparison of similarities to this invention.